PTL 1 discloses a wind turbine generator that performs power generation using wind flow.
The wind turbine generator includes a tower that stands on the ground surface, a nacelle, a main shaft, a rotor head, a plurality of blades, and a pitch axis rotation mechanism.
The nacelle (rear nacelle) is provided on the tower. The main shaft is rotatably provided in the nacelle. The rotor head (front nacelle) is provided at a front tip of the main shaft, and projects from the nacelle. The plurality of blades radially protrude, from the rotor head about an axis of the main shaft. The pitch axis rotation mechanism (variable pitch device) rotates the blades about a pitch axis thereof.
In the wind turbine generator according to the Patent Document 1, the pitch axis rotation mechanism includes an actuator (hydraulic cylinder) that has an actuator main body which is fixed to the nacelle, and a rod which is stretchable from the actuator main body, and a link structure that links the rod with the blades.
The link structure includes a pitch control shaft that is connected to a front tip of the rod via a rod bearing section, and a plurality of joints (links and arms) that connects the pitch control shaft with the blades.
The pitch control shaft reaches the inside of the rotor head through a power generator of the nacelle and the main shaft. The pitch control shaft can reciprocate in a direction of the axis of the main shaft by the stretching of the rod with respect to the actuator main body. The pitch control shaft can be rotated with respect to the rod by the rod bearing section.